Fracturing system

ABSTRACT

A fracturing system includes an energy storage having a battery and a switch, a switch cabinet, a plurality of transformers, a plurality of rectifiers, and a plurality of inverters respectively corresponding to and connected with a plurality of fracturing apparatuses. The switch cabinet is connected with the plurality of transformers. The plurality of transformers are respectively connected with the plurality of rectifiers. Each of the plurality of rectifiers is directly connected with a DC bus and the energy storage. The DC bus is directed connected to the plurality of inverters. The energy storage is directly electrically connected with the DC bus or each of the plurality of inverters. The energy storage is configured to power the plurality of fracturing apparatuses.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application of U.S. Pat.Application No. 17/747,916, filed on May 18, 2022, entitled “FRACTURINGSYSTEM,” which is a continuation application of U.S. Pat. ApplicationNo. 17/167,391, filed on Feb. 4, 2021, entitled “FRACTURING SYSTEM,”which claims priority to Chinese Patent Application No. 202022752009.1,filed on Nov. 24, 2020. U.S. Pat. Application No. 17/747,916 is also acontinuation application of International Application No.PCT/CN2020/137135 filed on Dec. 17, 2020, which claims priority toChinese Patent Application No. 202022752009.1, filed on Nov. 24, 2020.The entire contents of all of the above-identified applications areincorporated herein by reference in their entirety.

FIELD OF INVENTION

The present disclosure generally relates to a fracturing system.

BACKGROUND

Fracturing is a major measure for stimulating oilfield productions.Limited by issues such as construction cost and environmental pollution,electrical equipment has been gradually applied to provide driving forcefor oilfield site construction, that is, electric driving fracturingconstruction. For example, the fracturing system can be connected to andpowered by electricity grid; or electricity generating equipment can bemounted on site to supply electrical energy; or both the electricitygrid and the electricity generating equipment can be jointly applied tosupply combined electrical energy to the fracturing system. However,there are still the following problems in fracturing operation usingelectric drive:

1. At present, gas turbines are widely used to drive generators forelectricity generation, which has high thermal efficiency and goodeconomy. However, gas turbines usually need to be equipped withblack-start devices to start the generator. Multiple black-starts(usually power equipment driven by diesel engines) are required whenthere are multiple generators, leading to redundancy of start devices.In addition, diesel fuel is also required. These problems increasevariety and complexity of equipment at the well site.

2. The scale of fracturing operation is usually large. For example, thepower of shale gas fracturing can usually reach 20,000-50,000 WHP. Ifall equipment is driven by electrical energy, power about 25 MW isneeded. Therefore, it is necessary to ensure sufficient generator power.The placement of gas treatment equipment should also be considered whenarranging electricity generating equipment at the well site. Consideringsafety problems (such as operation failure caused by abnormal powerfailure, which leads to failure of expected effect, even safetyaccidents), it is also necessary to arrange backup electricitygenerating equipment. All of these conditions result in a relativelylarge area occupied by electricity generating equipment. In addition,flattening ground is needed to arrange electricity generating equipment,however, most well sites are located in the wild, even in mountains,where flattening ground needs additional cost to obtain This furtherincreases the cost of fracturing operations.

3. Fracturing operation site usually keeps continuous high-poweroperations lasting about 2-4 hours. In the clearance period, inspection,wellhead switching, perforation and other work are performed, thenhigh-power operations are performed again. In other words, the electricload of fracturing operation fluctuates greatly. If the generator set iskept idling during the clearance period when almost no electrical energyis needed, it will cause a waste of fuel. Otherwise, if some or all ofthe generators are started and stopped frequently along with thefracturing construction process, it may lead to high cost and reductionof the generator’ s service life.

4. There are limitations to the power of a single generator. Forexample, when operating at a high temperature the electricity generationcapacity of the gas turbine will decrease. Therefore, overload risks mayoccur to electricity generating equipment at the well site under someworking conditions.

5. Fuel supply issues should be usually considered when electricitygenerating equipment is driven by internal combustion engines. Theconsumption of liquid or gas fuel is large. Although multiple generatorscan be backed up, fuel supply systems and pipelines are usually unableor difficult to be backed up, especially for gas that requires on-sitetreatment, such as wellhead gas, there being risk of fuel supplyinterruption. In order to solve these problems, measures such astemporary storage of fuel needs to be considered at well site.

6. When the fracturing system is powered by the electricity grid, thereis limitation to the fluctuation of electric power supplied by theelectricity grid. Moreover, the stability of construction operation isdirectly affected by the stability of electricity grid, thus there is arelatively large risk of stability.

7. Some well sites are located in areas where there are usually noready-made electricity supply facilities and need to be prepared inadvance, resulting in higher costs and cycle costs.

8. In the case of offshore platform operations, there are problems oflimited placement area and energy supply.

Therefore, there is a need for a fracturing system to at least partlysolve the foregoing problems.

SUMMARY

An objective of the present disclosure is to provide a fracturingsystem.

According to an aspect of the present disclosure, a fracturing systemincludes: a functional unit configured to perform procedures offracturing operations; an electricity supply unit electrically connectedto the functional unit, the electricity supply unit being configured tosupply electrical energy to the functional unit; and an energy storageunit electrically connected respectively with the electricity supplyunit and the functional unit, the energy storage unit being configuredto store electrical energy from the electricity supply unit and supplyelectrical energy to the functional unit.

According to the present disclosure, the fracturing system includes anenergy storage unit, which can store surplus electrical energy of theelectricity supply unit and then supply electrical energy to the wholefracturing system when needed, thereby playing a role of energy storageand peak regulation, enabling the generator set and the like to maintaineconomic working condition for a long time, being safer and more stable,thus improving the efficiency and economy of the generator set. Inaddition, it is possible to generate electricity from non-carbon sourcesfor fracturing operations. Moreover the fracturing system furtherminimizes the use of internal combustion engines, which is moreenvironment-friendly. The present disclosure can also reduce the numberof generator sets and the space occupied by the generator sets so as toreduce the construction cost of fracturing operations.

In one embodiment, the electricity supply unit includes a generator set,and the energy storage unit is configured to supply electrical energy tothe generator set.

According to the present disclosure, the energy storage unit can providenecessary electrical energy for starting the generator set before thegenerator set starts.

In one embodiment, the fracturing system further includes a switchcabinet, a transformation unit, and a frequency conversion unit. Theelectricity supply unit is electrically connected with the functionalunit via the switch cabinet, the transformation unit, and the frequencyconversion unit. Wherein the energy storage unit is electricallyconnected with the functional unit through the switch cabinet, thetransformation unit and the frequency conversion unit, or the energystorage unit is electrically connected with the functional unit via thetransformation unit and the frequency conversion unit.

According to the present disclosure, the current supplied by theelectricity supply unit to the functional unit can be controlledcentrally, and the current can be transformed, rectified, and convertedinto the current that is suitable for the functional unit. In addition,the mode of electrical connection between the energy storage unit andthe functional unit can be flexibly selected according to actual needs.

In one embodiment, the frequency conversion unit includes a rectifiermodule and an inverter module, wherein the transformation unit isintegrated with the rectifier module, the inverter module is integratedwith a power element of the functional unit, the rectifier module iselectrically connected with the inverter module via a DC bus, and theenergy storage unit is electrically connected with the DC bus or theinverter module.

According to the present disclosure, the rectifier module and theinverter module are arranged as two separate parts, and the output endof the energy storage unit can be selectively connected to the DC bus orthe inverter module according to needs, thereby enhancing theflexibility of the arrangement.

In one embodiment, the charging interface of the energy storage unit iselectrically connected with the rectifier module.

According to the present disclosure, the current input to the energystorage unit can be rectified with an appropriate frequency and voltage.

In one embodiment, the electricity supply unit, the energy storage unit,and the functional unit are electrically connected in series.

According to the present disclosure, the energy storage unit can form apart of the circuit through which electrical energy is supplied from theelectricity supply unit to the functional unit, thus increasing theselectivity of the arrangement.

In one embodiment, the energy storage unit includes a battery module, aswitch, a battery management module, a charging interface, and anelectric supply interface.

According to the present disclosure, the energy storage unit can beconveniently controlled and managed through a battery management moduleas well as a switch.

In one embodiment, the energy storage unit further includes anadditional rectifier module electrically connected between the charginginterface and the battery module, or the energy storage unit furtherincludes an additional inverter module, the electric supply interfaceincludes an AC electric supply interface, wherein the additionalinverter module is electrically connected between the battery module andthe AC electric supply interface.

According to the present disclosure, the additional rectifier module canrectify the current input to the energy storage unit into directcurrent, or the energy storage unit can output alternating current, andthe additional inverter module can convert the current output by theenergy storage unit with appropriate frequency and voltage.

In one embodiment, the energy storage unit further includes a DC/DCconverter electrically connected between the charging interface and thebattery module and/or between the battery module and the electric supplyinterface.

According to the present disclosure, the effect of increasing ordecreasing of DC voltage can be achieved inside the energy storage unit.

In one embodiment, the electric supply interface includes a DC electricsupply interface which is electrically connected with the battery moduledirectly.

According to the present disclosure, the energy storage unit can outputdirect current.

In one embodiment, the energy storage unit includes a bidirectionalconverter, and the charging interface and the electric supply interfaceare respectively electrically connected with the battery module via thebidirectional converter.

According to the present disclosure, the bidirectional converter has afunction of rectification and inversion, thereby controlling thecharging and discharging function of the energy storage unit.

In one embodiment, the fracturing system further includes a centralizedcontrol unit which is in communication connection with the functionalunit and the energy storage unit in a wired and/or wireless manner, andthe centralized control unit is used for monitoring and/or controllingworking parameters of the functional unit and the energy storage unit.

According to the present disclosure, the working parameters of keyequipment can be controlled, and the energy storage unit can bemonitored and protected.

In one embodiment, the centralized control unit is configured to sendout alarm information and/or reduce the power consumption of thefunctional unit when voltage, current and/or frequency of power supplyto the functional unit deviate from a predetermined range.

According to the present disclosure, when the energy storage unit and/orthe electricity supply unit fails, the electrical energy transmitted tothe functional unit can be reduced to avoid safety accidents, at thesame time, an alarm message can be sent for caution.

In one embodiment, the centralized control unit is configured toautomatically control the energy storage unit to supply electricalenergy to the electricity supply unit, the centralized control unitand/or the functional unit when power supply from the electricity supplyunit is cut off.

According to the present disclosure, the switching between the powersupply from the electricity supply unit and from the energy storage unitcan be automatically realized.

In one embodiment, the centralized control unit is further configured tosend out prompt information including working duration informationprejudged according to remaining battery level of the energy storageunit and working power of the functional unit.

According to the present disclosure, it is possible to allow theoperators to take necessary measures to continuously completeoperations, or temporarily reduce power consumption, etc., so as toavoid operation accidents such as well blockage caused by suddenshutdowns.

In one embodiment, the centralized control unit controls the energystorage unit to operate in the following manner: all the battery modulesare charged at the same time; or all the battery modules supplyelectrical energy at the same time; or some of the battery modulessupply electrical energy and the others are charged.

According to the present disclosure, it is possible to select workingmode of the energy storage unit flexibly according to needs.

In one embodiment, the centralized control system is configured todisconnect the electrical connection for charging the energy storageunit when voltage, current and/or frequency for charging the energystorage unit deviate from a predetermined range.

According to the present disclosure, the charging circuit can be cut offwhen there are errors during charging in order to protect the energystorage unit.

In one embodiment, the energy storage unit is arranged on a carrier.

According to the present disclosure, the energy storage unit can betransported easier. The carrier includes: auxiliary lifting appliance,semi-trailer, chassis vehicle, rail vehicle, base for lifting, skid,etc. which can transport the energy storage unit to a power stationlocated off the well site for centralized charging.

In one embodiment, the electricity supply unit includes at least one ofan electricity grid, a diesel generator set, a turbine generator set, agas generator set, a nuclear reactor generator set, a photovoltaicelectricity generating equipment, wind turbine electricity generatingequipment and a fuel cell, wherein the fuel cell can be a natural gasfuel cell, a hydrogen fuel cell, and the like.

According to the present disclosure, it is possible to select thespecific form of the appropriate power supply unit according to actualneeds.

BRIEF DESCRIPTION OF THE DRAWINGS

For the sake of better understanding on the above and other objectives,features, advantages, and functions of the present disclosure, thepreferred embodiments are provided with reference to the drawings. Thesame reference symbols refer to the same components throughout thedrawings. It would be appreciated by those skilled in the art that thedrawings are merely provided to illustrate preferred embodiments of thepresent disclosure, without suggesting any limitation to the protectionscope of the present disclosure, and respective components therein arenot necessarily drawn to scale.

FIG. 1 is a schematic diagram of a first configuration of an energystorage unit used in a fracturing system according to the presentdisclosure;

FIG. 2 is a schematic diagram of a second configuration of an energystorage unit used in a fracturing system according to the presentdisclosure;

FIG. 3 is a schematic diagram of a third configuration of an energystorage unit used in a fracturing system according to the presentdisclosure;

FIG. 4 is a schematic diagram of a fourth configuration of an energystorage unit used in a fracturing system according to the presentdisclosure;

FIG. 5 is a schematic diagram of a fifth configuration of an energystorage unit used in a fracturing system according to the presentdisclosure;

FIG. 6 is a schematic diagram of a sixth configuration of an energystorage unit used in a fracturing system according to the presentdisclosure;

FIG. 7 is a schematic diagram of a fracturing system according to afirst embodiment of the present disclosure;

FIG. 8 is a schematic diagram of a fracturing system according to asecond embodiment of the present disclosure;

FIG. 9 is a schematic diagram of a fracturing system according to athird embodiment of the present disclosure;

FIG. 10 is a schematic diagram of a fracturing system according to afourth embodiment of the present disclosure;

FIG. 11 is a schematic diagram of a fracturing system according to afifth embodiment of the present disclosure;

FIG. 12 is a schematic diagram of a fracturing system according to asixth embodiment of the present disclosure;

FIG. 13 is a schematic diagram of another connection configuration ofthe energy storage unit of the fracturing system shown in FIG. 12 ;

FIG. 14 is a schematic diagram of a fracturing system according to aseventh embodiment of the present disclosure;

FIG. 15 is a schematic diagram of a modification of the fracturingsystem according to the seventh embodiment of the present disclosure;and

FIG. 16 is a system block diagram of the fracturing system according tothe present invention.

List of reference symbols 10 functional unit (or referred to asfracturing equipment) 20 electricity supply unit (or referred to aselectricity supplier) 30 energy storage unit (or referred to as energystorage) 40 switch cabinet 50 transformation unit (or referred to astransformer) 60 frequency conversion unit (or referred to as frequencyconverter) 61 rectifier module (or referred to as rectifier) 62 invertermodule (or referred to as inverter) 21 non-carbon energy electricitygenerating module (or referred to as non-carbon energy electricitygenerator) 22 carbon energy electricity generating module (or referredto as carbon energy electricity generator) 100/200/300/400/500/600/700fracturing system

DETAILED DESCRIPTION OF EMBODIMENTS

Reference now will be made to the drawings to describe embodiments ofthe present disclosure. What will be described herein are only preferredembodiments according to the present disclosure. On the basis, thoseskilled in the art would envision other embodiments of the presentdisclosure which all fall into the scope of the present disclosure.

The present disclosure provides a fracturing system for fracturingoperation at oil and gas fields. As shown in FIG. 16 , according to thepresent disclosure, the fracturing system mainly comprises a functionalunit, an electricity supply unit, an energy storage unit, and acentralized control unit. Wherein the functional unit mainly includesfunctional equipment and/or components for performing each procedure ofthe whole fracturing operation, for example, the functional units mayinclude mixing equipment, sand blender, sand conveyor, fracturingequipment, or cementing equipment and batch mixing equipment used incementing operations, or electric drive equipment in drilling operation,etc. Wherein mixing equipment, sand blender, sand conveyor, fracturingequipment and the like may include power elements to provide drivingforce, all or most of which are electric motors. In other words,according to the present disclosure, all or most of the fracturingsystem is electrically driven.

The electricity supply unit is electrically connected with eachelectrically driven power element of the functional unit and provideselectrical energy so that each part of the functional unit can realizeits function. Specifically, the electricity supply unit may include oneof an electricity grid, a diesel generator set, a turbine generator set,a gas generator set, a nuclear reactor generator set, photovoltaicgeneration equipment, a wind power plant and a fuel cell or acombination of one or more of the above-mentioned. Those skilled in theart can flexibly select the specific form of the electricity supply unitaccording to actual situation of the well site. In addition, theelectricity supply unit can also be electrically connected with thecentralized control unit to supply electrical energy to the centralizedcontrol unit.

The centralized control unit is usually located in a fracturinginstrument vehicle or a remote command center, and can be incommunication connection with the functional unit in a wired or wirelessmanner. The centralized control unit can be respectively incommunication connection with the functional unit, the electricitysupply unit, and the energy storage unit. Therefore, the centralizedcontrol unit can be used for monitoring or controlling pressure offracturing equipment, temperature, and rotational speed parameters ofkey devices at the well site, as well as running parameters, such asrotational speed of electric motor of fracturing pump vehicle,rotational speed of electric motor for heat dissipation of fracturingequipment, rotational speed of electric motor of sand blender and mixingequipment. The centralized control unit may have a local control mode ora remote control mode.

The energy storage unit is electrically connected with the electricitysupply unit, the functional unit, and the centralized control unitrespectively. On the one hand, the energy storage unit can storeelectrical energy from the electricity supply unit; on the other hand,the energy storage unit can also be used as a backup of the electricitysupply unit or as a supplement to supply electrical energy to thefunctional unit.

A specific charging process can be as follows:

For example, in an embodiment that the electricity supply unit includesa generator set, the fracturing equipment of the functional unit isconfigured to stop working during clearance of fracturing operation,while the generator set still keeps a working condition of highgenerating efficiency to charge the energy storage unit, so as to avoidfrequent start and stop of the generator set or idling running of thegenerator set which will lead to a waste of fuel and energy.

Alternatively, during the fracturing operation process, surpluselectrical energy can be stored in the energy storage unit whengenerating capacity of the generator set is higher than electric powerneeded in actual working condition of the functional unit, therebyenabling the generator set to keep a steady and efficient runningcondition.

A specific electrical energy supply process can be as follows:

For example, the need for electric power is low in the clearance of thefracturing operation or in a preparation stage of pre-fracturingoperation when most of the fracturing equipment stop working. Hence thefracturing operation can be power supplied by the energy storage unitdirectly with the generator set being shut down and the electricity griddisconnected.

Alternatively, when the generator set or the electricity grid fails toprovide electrical energy for the electrical equipment, the energystorage unit can be used to provide electrical energy so as to ensurethe normal operation of the electrical equipment, thereby avoidinginterruption of fracturing operation due to power supply problem, andfurther avoiding safety problems such as well plugging caused byinterruption of fracturing operation.

Alternatively, the energy storage unit can also supply electrical energyto other important communication, monitoring and control equipment suchas centralized control unit, control module of generator set, controlmodule of other equipment, and monitoring system of well site, etc., soas to ensure the reliability of key systems such as communication andcontrol system when the power equipment or the electricity grid fail.

Alternatively, under the condition that the electric capacity of theenergy storage unit is large enough to meet the power demand duringfracturing operation, the energy storage unit or the electricity supplyunit can be selectively used to alternately provide electrical energyfor fracturing operation. For example, when the air temperature isappropriate or under other conditions that are suitable for internalcombustion engine power generation, the generator set can be used tosupply electrical energy, while during low power consumption periods,the electricity grid, photovoltaic and wind turbine can be used tosupply electrical energy, with the energy storage unit being charged atchosen time meanwhile. Under some other conditions such as the airtemperature is too high to use the above-mentioned power generationmethods to supply electrical energy, or during the period of peakelectricity consumption, the energy storage unit can be used forelectric energy supply so as to enhance economic efficiency. At thistime, a part of the energy storage unit can be used as a backup powersupply to ensure the safety and stability of power supply at the wellsite.

FIGS. 1 to 6 respectively show various configurations of an energystorage unit for a fracturing system according to the presentdisclosure.

As shown in FIG. 1 , the energy storage unit includes a battery modulefor storing electrical energy. The battery module may specifically bechemical batteries and/or super capacitors or a combination of one ormore of the above, etc. Wherein the chemical battery may be, forexample, a lithium ion battery, a sodium ion battery, or a lithium ironphosphate battery, etc.

In addition, although not shown in the drawings, it can be understoodthat in order to realize the functions of storing and supplyingelectrical energy by the battery module, the energy storage unit alsoincludes a battery management module, a charging interface, an electricsupply interface, a switch, and the like. The battery module can beelectrically connected with the electricity supply unit via the charginginterface and can be electrically connected with components needingpower supply via the electric supply interface. The switch is used tocontrol the on-off state of the electrical connection between the energystorage unit and other units. The battery management module can detectthe key parameters of the battery module so as to protect the energystorage unit, such as under-voltage protection, overload protection,overcurrent protection, short circuit protection and over-temperatureprotection, etc. The battery management module may also have a minimumprotected battery level. For example, the battery management module maybe set a minimum protected battery level to ensure that the batterymodule stores sufficient backup battery level or achieve the purpose ofprotecting the battery. When approaching, reaching, or falling below theset minimum protected battery level, the battery management modulegenerates a corresponding instruction or cuts off the output powersupply, such as sending out a prompt message.

In addition, the battery management module can be in communicationconnection with the centralized control unit of the fracturing systemthrough wired, wireless, Ethernet and other communication methods. Thecentralized control unit can control the charging and power supplyoperation of the energy storage unit in a local control mode or a remotecontrol mode. For example, the centralized control unit can control partof the battery modules of the energy storage unit to be charged whilethe other part of the battery modules to supply electrical energy; orthe centralized control unit can control all battery modules to becharged at the same time; or the centralized control unit can controlall battery modules to supply electrical energy at the same time. Acharging protection program can also be set. When the frequency,current, voltage and temperature of charging are abnormal, the chargingprotection program can cut off the charging power supply to avoid safetyaccidents.

In addition, the centralized control unit can monitor the parameters ofthe energy storage unit such as battery level, temperature, current,voltage, etc. and can display these parameters to the operator. When theelectricity supply unit or the energy storage unit is abnormal, thecentralized control unit can judge the abnormal situation according tocollected signals, and then display alarm information, or promptoperation precautions, or automatically control the functional unit,such as reducing power consumption, specifically, reducing VFD outputcurrent or closing part or all of VFD output, or reducing flushing timesof some fracturing pumps, etc. When an emergency occurs at the wellsite, the centralized control unit can be used for emergency shutdown.The centralized control unit can also turn off an output switch of theelectricity supply unit or the electricity supply unit itself through aremote stop button or a remote stop command on the touch screen,specifically, for example, stopping running of turbine generator, orturning off an output switch of the energy storage unit or the energystorage unit itself, or stopping output current of VFD.

When the electricity supply unit stops supplying power due to emergencyshutdown, the centralized control unit can automatically adjust powersupply function of the energy storage unit according to presetconditions. For example, when turbine generator stops running, thecentralized control unit can control the energy storage unit to supplypower to the turbine engine, the centralized control unit, and the likein an automatic or manual manner through a remote control mode or alocal control mode so as to ensure engine lubrication, heat dissipationand stability of the centralized control unit.

When the electricity supply unit stops supplying electrical energy dueto an emergency, the centralized control unit can adjust the powersupply function of the energy storage unit according to a preset programin order to continue supplying power for the functional units necessaryfor operation at the well site, at the same time, the centralizedcontrol unit sends out prompt information to operator. The promptinformation can include a prejudged operation duration informationaccording to operation situation (inferring electrical energyconsumption based on current power consumption or preset operatingparameters of different stages of functional units), so that theoperators can take necessary measures to continuously complete theoperation, or temporarily reduce power consumption, etc., to avoidoperation accidents such as well blockage caused by sudden shutdown.

FIG. 2 shows a second configuration of energy storage unit. Comparedwith the energy storage unit shown in FIG. 1 , the energy storage unitshown in FIG. 2 further includes an additional rectifier moduleelectrically connected between the charging interface and the batterymodule. The additional rectifying module can rectify charging currentinput to the energy storage unit, changing it from alternating currentinto direct current and providing sufficient charging voltage to thebattery module. That is, the additional rectifying module can play arole of charging.

FIG. 3 shows a third configuration of energy storage unit. Compared withthe energy storage unit shown in FIG. 2 , the energy storage unit shownin FIG. 3 further includes an additional inverter module electricallyconnected between the battery module and the electric supply interface.The additional inverter module can convert direct current output by thebattery module into alternating current with constant frequency andvoltage or frequency modulation and voltage regulation. Therefore, theenergy storage unit according to the third configuration can outputalternating current. Correspondingly, the electric supply interfaceelectrically connected with the additional inverter module is an ACelectric supply interface.

FIG. 4 shows a fourth configuration of energy storage unit. Comparedwith the energy storage unit shown in FIG. 1 , the energy storage unitshown in FIG. 4 further comprises a bidirectional converter. Thecharging interface and the electric supply interface of the energystorage unit are respectively electrically connected with the batterymodule through the bidirectional converter. The bi-directional convertercan achieve conversion between DC and AC, control the charging anddischarging process of the battery module, realize regulation of activepower and reactive power of the electricity grid, and can also directlysupply electrical energy to AC load without the electricity grid.

FIG. 5 shows a fifth configuration of energy storage unit. Compared withthe energy storage unit shown in FIG. 3 or FIG. 4 , the energy storageunit shown in FIG. 5 further includes a DC/DC converter. The DC/DCconverter is arranged in series between the additional rectificationmodule and the battery module as well as the battery module and theadditional inverter module. The DC/DC converter can transform and adjustDC voltage input to the battery module as well as DC voltage output fromthe battery module. Of course, as an alternative embodiment, a DC/DCconverter may be provided only between the additional rectificationmodule and the battery module, or only between the battery module andthe additional inverter module. In addition, the additional rectifiermodule and the additional inverter module can be replaced with abidirectional converter to adjust current characteristics. In addition,it is also possible to omit the additional rectifier module and theadditional inverter module with only the DC/DC converter being provided.

FIG. 6 shows a sixth configuration of energy storage unit. Compared withthe energy storage unit shown in FIG. 3 , the energy storage unit shownin FIG. 6 further comprises a DC electric supply interface. The DCelectric supply interface is directly electrically connected with thebattery module in parallel with the additional inverter module and theAC electric supply interface. Therefore, according to the sixthconfiguration, the energy storage unit can simultaneously outputalternating current and direct current.

FIGS. 7 to 12 respectively show fracturing systems of differentembodiments according to the present disclosure. The following is adetailed description with reference to the accompanying drawings.

As shown in FIG. 7 , in a first embodiment, in addition to a functionalunit 10, an electricity supply unit 20, and an energy storage unit 30described above, fracturing system 100 preferably further comprises aswitch cabinet 40, a transformation unit 50 and a frequency conversionunit 60. The switch cabinet 40 is used to centrally control branching,merging, on-off state and the like of electrical connections betweenvarious functional devices and/or components from the electricity supplyunit 20 to the functional unit 10. It can be understood that when theelectricity supply unit 20 and the energy storage unit 30 are connectedto the switch cabinet 40 at the same time, the switch cabinet 40 can beinterconnected or connected separately. The transformation unit 50 andthe frequency conversion unit 60 are located between the switch cabinet40 and the functional unit 10 which are used for transforming,rectifying and frequency converting current input to the functional unit10. Wherein, the transformation unit 50 may include a transformer. Thefrequency conversion unit 60 may include a frequency converter(Variable-frequency Drive, VFD). Wherein, there are respectively atleast one transformation unit and one variable frequency unit,preferably two or more groups, so that AC variable-frequency currentswith different voltages can be output.

The charging interface of the energy storage unit 30 is electricallyconnected to a power generation port of the electricity supply unit 20.And the electric supply interface of the energy storage unit 30 isconnected with an input end of the switch cabinet to supply electricalenergy to the functional unit 10.

FIG. 8 shows a fracturing system 200 according to a second embodiment ofthe present disclosure, which is substantially the same as thefracturing system 100 of the first embodiment shown in FIG. 7 . Thedifference is that, in the fracturing system 200, the electricity supplyunit 20 includes a generator set, such as a turbine generator set or thelike. The electric supply interface of the energy storage unit 30 may beelectrically connected to a power consumption port of the electricitysupply unit 20. Thus, the energy storage unit 30 can not only supplyelectrical energy to the functional unit 10 but also to the electricitysupply unit 20. For example, before the generator set is started, theenergy storage unit 30 can provide the electricity supply unit 20 withthe electrical energy required to start; or when the generator set isshut down, the energy storage unit 30 can provide the necessaryelectrical energy to the generator set to ensure normal running of heatdissipation system or lubrication system of the generator set.

In addition, in the fracturing system 200, the energy storage unit 30may also be directly electrically connected to the functional unit 10through the transformation unit 50 and the frequency conversion unit 60without passing through the switch cabinet 40. In this case, the on-offstate of the electrical connection between the energy storage unit 30and the functional unit 10 can be controlled by the switch of the energystorage unit 30 itself.

FIG. 9 shows a fracturing system 300 according to a third embodiment ofthe present disclosure, which is substantially the same as thefracturing system 200 of the second embodiment shown in FIG. 8 . Thedifference is that, in the fracturing system 300, the energy storageunit 30 is directly electrically connected with the switch cabinet 40,while the electricity supply unit 20 is electrically connected with theswitch cabinet 40 via the energy storage unit 30. Therefore, the energystorage unit 30 is used to provide electrical connection from theelectricity supply unit 20 to the functional unit 10 in addition to thefunction of storing electrical energy. In other words, in the fracturingsystem 300, the electricity supply unit 20, the energy storage unit 30and the functional unit 10 are connected in series.

FIG. 10 shows a fracturing system 400 according to a fourth embodimentof the present disclosure, wherein the electricity supply unit isomitted. In the fracturing system 400, the energy storage unit 30 may bemoved by a carrier such as a truck or trailer. Such an arrangement mayallow a power station to be arranged outside the well site, and theenergy storage unit 30 may be transported outside the well site forcentralized charging by means of a carrier.

FIG. 11 shows a fracturing system 500 according to a fifth embodiment ofthe present disclosure, which is substantially the same as thefracturing system 200 of the second embodiment shown in FIG. 8 . Thedifference is that, in fracturing system 500, the frequency conversionunit is divided into a rectifier module 61 and an inversion module 62.Wherein the rectifier module 61 and the transformation unit 50 areintegrated as a single device, and can supply rectified current to sandblender, mixing equipment, fracturing equipment, and other devices ofthe functional unit 10. In addition, sand blender, mixing equipment,fracturing equipment and other devices all include inverters andelectric motors. The inverter of each device constitutes the invertermodule 62. The rectifier module 61 may be electrically connected to theinverter module 62 through a DC bus. This arrangement can improve theflexibility of the arrangement of each unit in the fracturing system500.

The energy storage unit 30 outputs direct current, and its electricsupply interface bypasses the switch cabinet 40, the transformation unit50 and the rectifier module 61, and is directly electrically connectedto inverters of various devices of the functional unit 10 or directlyconnected to DC buses.

FIG. 12 shows a fracturing system 600 according to a sixth embodiment ofthe present disclosure, which is substantially the same as thefracturing system 500 of the fifth embodiment shown in FIG. 11 . Thedifference is that, in fracturing system 600, the charging interface ofthe energy storage unit 30 is electrically connected to a rectifiermodule 61 rather than directly connected with the electricity supplyunit 20. In this way, current input to the energy storage unit 30 isrectified DC current, so that the additional rectifier module can beomitted from the energy storage unit 30. Similar to the fracturingsystem 500 according to the fifth embodiment, the electric supplyinterface of the energy storage unit 30 is directly electricallyconnected to inverters of various devices of the functional unit 10, oras shown in FIG. 13 , is directly electrically connected to a DC busbetween the rectifier module 61 and the inverter module 62.

FIG. 14 shows a fracturing system 700 according to a seventh embodimentof the present disclosure. In the seventh embodiment, the electricitysupply unit 20 may only comprises a non-carbon energy electricitygenerating module 21, such as solar energy electricity generatingequipment, wind turbine electricity generating equipment, hydrogen fuelcell, etc., so that the fracturing system 700 is completely powered bythe non-carbon energy. This can reduce the use of carbon energyelectricity generating equipment, thus reducing carbon emissions andachieving the effects of energy conservation and environmentalprotection.

More specifically, on the basis of comprising the non-carbon energyelectricity generating module 21, the electricity supply unit 20 mayalso comprise a carbon energy electricity generating module 22, such asa natural gas fuel cell, an internal combustion engine electricitygenerating device, etc. When the energy storage unit 30 needs to becharged, it can be selectively charged by the non-carbon energyelectricity generating module 21 or the carbon energy electricitygenerating module 22. Such an arrangement, on the one hand, can maximizethe use of non-carbon energy electricity generating equipment forelectricity generation, thereby reducing carbon emissions; On the otherhand, it can solve the problem of insufficient continuity of powersupplied from non-carbon energy sources. When non-carbon energy sourcescannot provide electrical energy (for example, when solar energyelectricity generating equipment cannot be used for night charging), thecarbon energy electricity generating module 22 can be flexibly selectedto supply electrical energy or charge the energy storage unit 30.

Specifically, as shown in FIG. 14 , the non-carbon energy electricitygenerating module 21 and the carbon energy electricity generating module22 are respectively electrically connected with the energy storage unit30 to charge it. The non-carbon energy electricity generating module 21is electrically connected to the switch cabinet 40 via the energystorage unit 30, and the carbon energy electricity generating module 22is directly electrically connected to the switch cabinet 40 torespectively supply power to the functional units 10. In addition, theelectric supply interface of the energy storage unit 30 is alsoelectrically connected with a power consumption port of the carbonenergy electricity generating module 22 to supply electricity generatingto the carbon energy electricity generating module 22.

FIG. 15 shows a modification of the fracturing system 700 of the seventhembodiment. In this modification, the charging interface of the energystorage unit 30 can only be electrically connected to the non-carbonenergy electricity generating module 21. That is, the energy storageunit 30 is only charged by the non-carbon energy electricity generatingmodule 21. However, an electricity generating port of the carbon energyelectricity generating module 22 is only electrically connected to theswitch cabinet 41, and a power consumption port of the carbon energyelectricity generating module 22 is electrically connected to theelectric supply interface of the energy storage unit 30. As a result,the carbon energy electricity generating module 22 supplies electricalenergy only to the functional unit 10, and the energy storage unit 30can supply electrical energy to the carbon energy electricity generatingmodule 22 when necessary. It can be understood that there is nocorrespondence between the different configuration of energy storageunits in the foregoing description and various embodiments of fracturingsystems. Under the premise of adaptation, one configuration of energystorage unit can be applied to fracturing systems of differentembodiments, for example, the energy storage unit shown in FIG. 3 can beapplied to fracturing system 100 according to the first embodiment,fracturing system 200 according to the second embodiment, and fracturingsystem 300 according to the third embodiment, etc. In addition, afracturing system may use different configurations of energy storageunits, for example, the fracturing system 100 according to the firstembodiment may use the energy storage units shown in FIGS. 2, 3 and 4 .

The fracturing system provided by the present disclosure comprises anenergy storage unit, the energy storage unit of the fracturing systemcan store redundant electrical energy of the electricity supply unit andsupply electrical energy to the whole fracturing system when needed,playing the role of energy storage as well as peak shaving so that thegenerator set and the like can keep economic working condition for along time, thus the system can be safe, stable, and achieve improvedefficiency and economy. In addition, the present disclosure makes itpossible to generate electricity from non-carbon sources for fracturingoperations. It minimizes the use of internal combustion engines thus ismore environment-friendly. The present disclosure can also reduce thenumber of generator sets and the space occupied by which so as to reducethe operation cost of fracturing operations.

The foregoing description on the various embodiments of the presentdisclosure has been presented to those skilled in the relevant fieldsfor purposes of illustration, but are not intended to be exhaustive orlimited to a single embodiment disclosed herein. As aforementioned, manysubstitutions and variations will be apparent to those skilled in theart. Therefore, although some alternative embodiments have beendescribed above, those skilled in the art can still envision or developother embodiments much more easily. The present disclosure is intendedto cover all substitutions, modifications and variations of the presentdisclosure as described herein, as well as other embodiments fallinginto the spirits and scope of the present disclosure.

I/We claim:
 1. A fracturing system, comprising: an energy storagecomprising a battery and a switch; a switch cabinet; a plurality oftransformers; a plurality of rectifiers; and a plurality of invertersrespectively corresponding to and connected with a plurality offracturing apparatuses, wherein: the switch cabinet is connected withthe plurality of transformers; the plurality of transformers arerespectively connected with the plurality of rectifiers; each of theplurality of rectifiers is directly connected with a DC bus and theenergy storage; the DC bus is directed connected to the plurality ofinverters; the energy storage is directly electrically connected withthe DC bus or each of the plurality of inverters; and the energy storageis configured to power the plurality of fracturing apparatuses.
 2. Thefracturing system according to claim 1, further comprising a generatorset, wherein the energy storage is configured to supply electricalenergy to the generator set.
 3. The fracturing system according to claim1, wherein: the energy storage is electrically connected with theplurality of fracturing apparatuses; and the plurality of fracturingapparatuses comprise mixing equipment, sand blender, sand conveyor,fracturing equipment, cementing equipment, batch mixing equipment, ordrilling equipment.
 4. The fracturing system according to claim 1,wherein the plurality of transformers are integrated with the pluralityof rectifiers, and the plurality of inverters are respectivelyintegrated with the plurality of fracturing apparatuses.
 5. Thefracturing system according to claim 1, wherein a charging interface ofthe energy storage is electrically connected with the plurality ofrectifiers.
 6. The fracturing system according to claim 1, wherein theenergy storage, and the plurality of fracturing apparatuses areelectrically connected in series.
 7. The fracturing system according toclaim 1, further comprising at least one power source of an electricitygrid, a diesel generator, a turbine generator, a gas generator, anuclear reactor generator, photovoltaic electricity generatingequipment, a wind power plant, and a fuel cell, wherein the energystorage is configured to be charged by the at least one power source. 8.The fracturing system according to claim 1, wherein the energy storagefurther comprises a charging interface and an additional rectifierelectrically connected between the charging interface and the battery.9. The fracturing system according to claim 1, wherein the energystorage further comprises an additional inverter and an electric supplyinterface, the electric supply interface comprises an AC electric supplyinterface, and the additional inverter is electrically connected betweenthe battery and the AC electric supply interface.
 10. The fracturingsystem according to claim 1, wherein the energy storage furthercomprises a charging interface, and an electric supply interface, andwherein a DC/DC converter electrically connected between the charginginterface and the battery and/or between the battery and the electricsupply interface.
 11. The fracturing system according to claim 1,wherein the energy storage further comprises an electric supplyinterface and wherein the electric supply interface comprises a DCelectric supply interface electrically connected with the batterydirectly.
 12. The fracturing system according to claim 1, wherein theenergy storage comprises a bidirectional converter, a charginginterface, and an electric supply interface, and wherein the charginginterface and the electric supply interface are respectivelyelectrically connected with the battery via the bidirectional converter.13. The fracturing system according to claim 1, further comprising acentralized control in communication connection with the plurality offracturing apparatuses and the energy storage via a wired and/or awireless connection, wherein the centralized control is configured tomonitor and/or control working parameters of the plurality of fracturingapparatuses and the energy storage.
 14. The fracturing system accordingto claim 13, wherein the centralized control is configured to send outalarm information and/or reduce a power consumption of the plurality offracturing apparatuses when a voltage, current, and/or frequency ofpower supply to the plurality of fracturing apparatuses deviate from apredetermined range.
 15. The fracturing system according to claim 13,wherein the centralized control is configured to automatically controlthe energy storage to supply electrical energy to the centralizedcontrol, and/or the plurality of fracturing apparatuses when powersupply to the fracturing system is cut off.
 16. The fracturing systemaccording to claim 15, wherein the centralized control is furtherconfigured to send out prompt information including working durationinformation that is based on (i) a remaining battery of the energystorage and (ii) a working power of the plurality of fracturingapparatuses.
 17. The fracturing system according to claim 13, whereinthe centralized control is configured to control the energy storage to:charge a portion of all batteries of the energy storage and supplyelectrical energy from a different portion of the batteries of theenergy storage at the same time.
 18. The fracturing system according toclaim 13, wherein the centralized control is configured to cut off anelectrical connection for charging the energy storage when a voltage,current, and/or frequency for charging the energy storage deviate from apredetermined range.
 19. The fracturing system according to claim 1,wherein the energy storage is arranged on a carrier.
 20. The fracturingsystem according to claim 1, further comprising a centralized control incommunication connection with the energy storage and configured tocontrol the energy storage to supply power to the plurality offracturing apparatuses alone.